The present invention relates generally to the field airbags. More specifically, the present invention relates to airbags using a tether and sleeve to control the shape of an airbag during inflation.
Under certain circumstances, it is desirable to deploy a vehicle airbag in what is known as a “low risk deployment” (LRD) mode. LRD modes are typically required when there is a chance that a deploying airbag may contact an out-of-position (“OOP”) occupant or, in certain cases, a rear facing infant seat. Typically, airbag systems are designed with electronic occupant sensing systems or airbag suppression mechanisms combined with appropriate inflator output controls to avoid such situations.
Conventional airbag systems either proposed or in production employ some form of vent in the airbag cushion or module which are mechanically linked to an active or passive release system. Other conventional airbag systems also employ some form of bar restraint tether in combination with the vent. These conventional systems, however, are relatively complex and less robust mechanically than might be required. Still, other conventional airbag systems are based upon venting gas early in the deployment of the airbag and depend upon the closing of a valve to assure a high-pressure airbag cushion for an occupant. However, these conventional systems may not contain enough gas for acceptable occupant protection if the valves fail to close.
In light of the above, there remains a continuing need in the art for improved airbag systems that are simple in design and easy to operate. There is also a need in the art for improved airbag systems that exhibit robust mechanical performance. Moreover, there is a need in the art for an airbag system that will still be filled with relatively high pressure inflation gas which would offer significant occupant impact protection, even though the airbag cushion may not have deployed to a full volume before being impacted by an occupant.